WONT START !!!

[tonyvan]

PUT THE NOBLE AWAY LAST SUNDAY AFTER A GOOD MORNING AT GOODWOOD SUPERCAR SUNDAY.WENT TO START THE OLD GIRL THIS MORNING TO GOT TO A CHARITY EVENT,AND THE FUEL PUMP WOULDNT BUZZ IN. TRIED CLEANING ALL 4 FUSES JUST ABOVE ECU, AND CHECK NONE WERE BLOWN. USED SOME WD40 ON THEM, AND ALSO ON THE BANK OF RELAYS ON THE BULKHEAD,BUT STILL NO JOY. THERE APPEARS TO BE POWER AT THE 2ND FUSE, 20 AMP ...NO VOLTAGE SHOWING AT THE FUEL PUMP WITH IGNITION ON.
ANY IDEAS IF THERE IS A RELAY OR HIDDEN FUSE SOMEWHERE IVE MISSED. I DONT THINK ITS THE IMMOBILISER.
THANKS
Tony

[Alpinestars]

Is it just the fuel pump not priming, ie, is there power? There is a fuse which cuts all power to the car. Located at the rear of the car, driver’s side, down by the battery. Otherwise it’s only ever been the fuses by the bulkhead in my experience.

[tonyvan]

That 80amp fuse is ok. there is voltage there. Some of the other fuses, click sensors on the engine when removed. Ignition light is on, but just no power to the fuel pump from what the multi meter reads, plus as its a high capacity fuel pump Bosch 400 which buzzes like a bh. Are there any fuel pump related relays or fuses on the passenger side footwell, or anywhere else ?

[Alpinestars]

You’ve exhausted what little knowledge I have. The only fuses that have been at fault when my fuel pump wasn’t pumping where the ones behind the bulkhead. I’m sure someone more knowledgeable will be along soon. ROB!!

[Blu3R]

If you've uprated the fuel pump then you should have fitted an inline fuse from either the battery or starter. Run your hand back along the power cable from the pump and I'll bet you'll find it.
Assuming that's good, check the condition (and integrity) of the earth from the pump back to chassis wherever you've chosen to mount it. Also check the studs on the pump haven't come loose and began to corrode.
Should be something simple like that if everything else is ok.

[951]

The pump is run via a relay that in turn is activated by the ECU isn't it?

If it's had the pump wiring mod, don't you usually add another relay?

On mine the relay is on the top n/s chassis rail near where the plate with the serial number is.

[tonyvan]

Thanks for the help guys. Yes there is a relay that is fitted on the cross section chassis, I don't recall seing another inline fuse but I will check. All contacts to the fuel pump are secure as I took them off to see if there was voltage at the terminals and also to fuel pump while it was isolated. Hoping it's a simple fix. Appreciate all ur input. Just to add, yes it does have the upgrade wiring for the fuel pump.
Tony

Edited by tonyvan on Monday 11th June 11:56

[Lofty999]

I'm no mechanic,but had a similar problem that turned out to be the ecu.Hope not for your sake but may be worth a look.Steve

[dave sutton]

I had a similar problem a few years back (pump not priming), it turned out to be a failed relay.

It had been fitted when the pump was upgraded.

On mine, the relay is located on the rear, n/s, just below the water header tank, see pic.



In my case, the failed relay kept blowing one of the fuses on the bulkhead behind the driver's seat, but, if it is the relay, in your case it may have stopped working in a less aggressive way.

[951]

tonyvan said:

Thanks for the help guys. Yes there is a relay that is fitted on the cross section chassis, I don't recall seing another inline fuse but I will check. All contacts to the fuel pump are secure as I took them off to see if there was voltage at the terminals and also to fuel pump while it was isolated. Hoping it's a simple fix. Appreciate all ur input. Just to add, yes it does have the upgrade wiring for the fuel pump.
Tony

Edited by tonyvan on Monday 11th June 11:56

You should see the "main" voltage at the relay, waiting to be switched in. If you don't, then find the fuse or break in the wiring.

If you do, you need to check the trigger voltage is getting there. You will only see the trigger voltage (to activate the relay to connect the main voltage to the pump) when the ECU first sends it. You need to check this at the same time as the ignition is initially turned on as the eco drops it off again after about 2 seconds once the priming time has elapsed.

If you don't see it, check the connection to the ecu. Or it could be the eco itself.

If you see both, the relay must be Fubar. (Or the pump)

[tonyvan]

Thanks guys for all ur help I won't be able to get to the car for a few days, but I will check the relay near the fuel pump and also see if there is voltage at tbat relay. Fingers crossed its not the Ecu as it will be pick ur price mr noble lol

[Midlifecrisis71]

Also worth considering that the immobiliser may be stuck on.
Not sure that the Nob immob uses a cut in power feed to the pup, but worth checking.
Disconnect battery for half an hour and reconnect, lock & unlock

[951]

Forgot to say, if you have had the fuel pump wiring upgrade the original relay may still be in use too - the original wiring that used to go to the pump may be used to pass the trigger to the new relay. Same logic checks apply there too. Just dropping a new relay(s) in is the easiest test.

Re your first post, you will never see voltage at the pump unless the engine is running, or for that very brief period after 'ignition on' when the ecu primes the pump.

[tonyvan]

Checked this eve and there is voltage to the relay near pump. Took it to halfords to match, but the relay I have is 12v 70 amp and they only has 12v 30 amp and two of the spade connectors are a lot smaller, so I will try a motor factors tommorow. Hoping it is just that relay.

[tonyvan]

Update took relay for the fuel jump to auto electrician who said the relay isn't switching in. Have to wait till Monday for a new relay to be ordered as its 70amp heavy duty one and not in stock anywhere local.fingers crossed that will cure the problem.

[tonyvan]

Thanks guys for all ur help got round to fitting new fuel Pump relay and alls good, the old girl started up. £12 fix lol

[Alpinestars]

Excellent

[Egilbergen]

Has anyone fitted a new heater resistor to a Noble M12

[alan-vkli4]

Thanks for the useful advice in the forum, which I'm a) new to and b) not very technical.

I've got a similar problem, fuel pump works every so often but then goes weeks without working so I can't get it anywhere to fix it. Not sure if it's immobiliser related or the relay but I thought I'd give the relay a go first.

Can anyone help me locate the relay, mine is M12 GTO 2.5 02 plate (original build #47). It's not in the same place as the picture earlier in the thread.

thanks
Alan

Edited by alan-vkli4 on Monday 16th July 14:58

[mgbond]

Could also just be a corroded bulkhead fuse as I have had that.